Juno RPC Proxy

A secure RPC proxy for Juno Cash nodes that provides authentication-free access for miners while protecting your node credentials. Also includes an optional ZMQ notification proxy for distributing block notifications to multiple miners.

Features

• RPC Method Whitelist: Only allows specified RPC methods, blocking potentially dangerous calls
• Credential Isolation: Miners connect without credentials; proxy handles upstream authentication
• ZMQ Proxy: Forwards block notifications from node to multiple miners (optional)
• Configurable Authentication: Optional authentication for miners connecting to the proxy

Requirements

• Go 1.21 or higher
• libzmq development libraries (for ZMQ proxy feature)

Install Dependencies (Ubuntu/Debian)

sudo apt-get install -y libzmq3-dev

Install Dependencies (CentOS/RHEL)

sudo yum install -y zeromq-devel

Install Dependencies (Windows)

1. Install Go (1.21 or higher)
2. Install MSYS2
3. Open MSYS2 MinGW64 terminal and install ZMQ:

   pacman -S mingw-w64-x86_64-zeromq

Building

Linux/macOS

go build -o juno-proxy

Windows

Using MSYS2 MinGW64 terminal:

go build -o juno-proxy.exe

Or using PowerShell with CGO enabled:

$env:CGO_ENABLED = "1"
go build -o juno-proxy.exe

Note: The ZMQ library requires CGO. Ensure your PATH includes the MinGW64 bin directory (e.g., C:\msys64\mingw64\bin) for the required DLLs at runtime.

Configuration

Copy the example configuration file and edit it:

cp config.example.toml config.toml

Basic Configuration

# Address and port to listen on
listen = "0.0.0.0:8233"

# RPC method whitelist - only these methods will be proxied
allowed_methods = [
    "getblocktemplate",
    "submitblock",
    "getblockchaininfo",
    "getmininginfo",
    "getblockhash",
    "getblock",
    "getbestblockhash",
]

# Upstream junocash node connection
[upstream]
url = "http://127.0.0.1:8232"
username = "rpcuser"
password = "rpcpassword"
timeout = "30s"

Proxy Authentication (Optional)

Enable authentication for miners connecting to this proxy if it's exposed to untrusted networks:

[proxy_auth]
enabled = true
username = "miner"
password = "minerpassword"

ZMQ Proxy Configuration

The ZMQ proxy feature forwards block notifications from your Juno Cash node to multiple miners. This is useful when:

• Running multiple miners that need instant block notifications
• Your node is on a different machine than your miners
• You want to reduce the number of ZMQ connections to your node

Node Configuration (junocashd.conf)

First, enable ZMQ notifications on your Juno Cash node. Add to ~/.junocash/junocashd.conf:

zmqpubhashblock=tcp://127.0.0.1:28332

Restart junocashd after making this change.

Proxy Configuration

Enable the ZMQ proxy in your config.toml:

[zmq]
enabled = true
upstream_url = "tcp://127.0.0.1:28332"  # Your node's ZMQ address
listen = "tcp://0.0.0.0:28333"          # Address miners connect to
topic = "hashblock"                      # Topic to forward (default)

Option	Description
enabled	Set to true to enable the ZMQ proxy
upstream_url	The ZMQ endpoint of your Juno Cash node
listen	The address where miners will connect for ZMQ notifications
topic	The ZMQ topic to subscribe/publish (default: hashblock)

Miner Configuration

Configure juno-miner to connect to the proxy's ZMQ endpoint instead of the node directly:

./juno-miner --rpc-url http://proxy-host:8233 --zmq-url tcp://proxy-host:28333

Usage

Running the Proxy

./juno-proxy -config config.toml

Command Line Options

• -config PATH - Path to configuration file (default: config.toml)
• -version - Show version and exit

Example Setup

                          ┌─────────────────┐
                          │   junocashd     │
                          │                 │
                          │ RPC: 8232       │
                          │ ZMQ: 28332      │
                          └────────┬────────┘
                                   │
                          ┌────────▼────────┐
                          │   juno-proxy    │
                          │                 │
                          │ RPC: 8233       │
                          │ ZMQ: 28333      │
                          └────────┬────────┘
                                   │
              ┌────────────────────┼────────────────────┐
              │                    │                    │
      ┌───────▼───────┐    ┌───────▼───────┐    ┌───────▼───────┐
      │  juno-miner   │    │  juno-miner   │    │  juno-miner   │
      │   Worker 1    │    │   Worker 2    │    │   Worker 3    │
      └───────────────┘    └───────────────┘    └───────────────┘

Security Notes

• The proxy isolates your node's RPC credentials from miners
• Use proxy_auth if the proxy is exposed to untrusted networks
• The method whitelist prevents miners from executing dangerous RPC calls
• Consider firewall rules to restrict access to the proxy

License

MIT License